RU2738702C2 - Improved frame elements for arrangement of monoliths - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: element for supporting monoliths containing catalysts in exhaust gases flow from combustion sources, comprising two pairs of opposite walls, in which the walls form a rectangular or square shape, an inner space formed by the walls, an inlet end, an outlet end, at least one locking element, at least one mat and at least one monolith comprising an inlet, outlet, four lateral sides and at least one catalyst, effective in reducing concentration of one or more gases in exhaust gases, in which at least one mat and at least one monolith are located inside the frame element such that at least one mat is located between the monolith and each adjacent wall, each blocking element is located across the inlet end or outlet end of the frame element and is connected to two opposite sides of the frame element.

EFFECT: improved frame elements for arrangement of monoliths.

15 cl, 15 dwg

Description

This invention relates to an improved frame member that supports catalyst containing monoliths within the frame, where the catalyst frame member is configured to be positioned in the exhaust stream from the engine.

BACKGROUND OF THE INVENTION

This invention relates to frame members used in catalytic modules for treating exhaust gases from stationary combustion sources having an exhaust system that passes exhaust gases through a support structure containing one or more monoliths, each of which contains one or more catalysts. A stationary combustion system can be any system that burns hydrocarbon-based fuels that are not used in road cars, trucks, or airplanes. They can be, for example, coal fired systems, liquid fuel (oil) fueled systems or gas turbines. Stationary combustion systems can also be applied to marine vessels where combustion systems such as diesel engines are used for large container ships or cruise ships. Stationary combustion systems usually operate in a continuous manner under constant, static load, while mobile combustion systems usually operate under varying loads.

Combustion of hydrocarbons in these systems and in engines used in mobile machinery, forms exhaust gases which must be processed to remove contaminants such as nitrogen oxides (NO _x), carbon monoxide (CO) and hydrocarbons (HC), which are formed ... NO _{x is} known to cause a range of health problems in humans and animals, as well as a range of environmental effects, including the formation of smog and acid rain. CO is toxic to humans and animals, and HC can cause adverse health effects. In order to reduce the exposure of people and the environment to these pollutants, especially NO _x , in the exhaust gases, it is desirable to eliminate these undesirable components, preferably through a process that does not generate other harmful or toxic substances.

Stationary combustion systems can be equipped with an emission control system that is equipped with catalytic modules. FIG. 1 is a depiction of a catalytic module known in the art. Catalyst modules are structures containing a plurality of frame elements, where each frame element may include a plurality of monoliths, each of which contains a catalyst carrier and one or more catalysts. The catalytic modules are installed in the flue gas duct of the emission control system and the flue gases to be purified flow through the monoliths during operation. The flue gas duct can typically have a cross-sectional area that is several square meters and can range from tens to hundreds of square meters. The dimensions of the flue gas duct can largely depend on many factors, including the size of the engine, the conditions under which the engine operates, the allowable back pressure, etc. In some cases, the flue gas duct may have a rectangular cross-section with a width and a duct height of several meters, for example 10 mx 10 m. The entire cross-sectional area of the flue gas duct is covered by one or more catalytic modules. The catalytic modules are positioned side by side so that all flue gases pass through the monoliths, contact the catalyst (s) on or in the monoliths and become purified. A plurality of catalyst modules, for example from two to five, can be arranged side by side in rows and columns, often included in a support frame, within the flue gas duct (FIG. 2). The catalytic modules themselves usually have a rectangular cross-section with an edge length of several meters.

In the direction of the flue gas flow, the catalytic modules are often arranged in several planes one behind the other. In some applications, catalyst modules can be extended several meters and even up to 10-15 meters in the direction of flow (Fig. 3). For some applications, such as marine or gas turbines, relatively harsh environmental conditions in terms of mechanical stresses may be present for the catalytic modules. For example, on sea-going vessels, there may be forces that are several times the force of gravity. In addition, especially for large cross-sections of catalytic modules used with gas turbines, mechanical stresses due to earthquakes must be taken into account.

The catalyst modules can be constructed using a stacking frame into which a plurality of frame member assemblies are inserted, where the frame members include monoliths containing one or more catalysts. The flue gas flows through the individual monoliths in the direction of the flue gas flow. Monoliths are also known as honeycomb catalysts. These honeycomb catalysts are typically made of ceramic material and have multiple channels for flowing through the monolith in the direction of gas flow. When installed, the flue gases flow through the flow channels in the monolith where they interact with the catalyst in the monolith or in the coating on the monolith's surface and become purified.

A typical problem faced with these processing systems is that the material is placed between the monoliths and parts of the frame elements in order to provide a seal and therefore gas tightness, i.e. no bypass flow around the catalyst, and also to act as a shock absorber against vibrations, cannot stay in place during normal use, unless the material is specially designed and provided as a special type of mat, which has a relatively high cost. The mat between the frame element and the monolith containing one or more catalysts is placed in the frame element just prior to welding the frame element. In situations where intermittent mechanical stresses occur, which are typical in exhaust system conditions, where engine vibration results in shock and vibration, the mat may move relative to the frame and monolith. This movement can lead to destruction of the monolith due to the relatively low mechanical stability of the system with respect to shock and vibration.

Modern frame elements have metal flaps or projections that partially cover the inlet and / or outlet surfaces of the monolith so that approximately 15% of the catalyst cells are not directly exposed to the exhaust gas stream.

Conventional element frames also have locking elements in the center of the inlet and outlet surfaces. One of the functions of the blocking element is to protect the gaps between the monoliths from the direct flow of exhaust gases. The blocking element is welded without pre-stressing, which results in relatively low mechanical stability with respect to shock and vibration.

Modern frame element designs do not provide a mechanism for joining frame elements directly to one another. The ability to attach frame elements to one another can eliminate the need for a catalytic module when only a small number of frame elements are required.

It would also be desirable to have a catalytic module that allows a cost-effective material to be interposed between the monoliths and the metal frame of the frame element to provide a seal and to act as a vibration damper that can stay in place during normal use and also provide the largest possible catalyst cross-section, all under conditions of severe mechanical stress.

SUMMARY OF THE INVENTION

In a first aspect, the present invention relates to a frame element for supporting monoliths containing catalysts in an exhaust gas stream from combustion sources, the frame element comprises two pairs of opposing walls, where the walls form a rectangular or square shape, an interior space defined by the walls, an inlet end, an outlet end, at least one blocking element, at least one mat, and at least one monolith comprising an inlet, an outlet, four sides and at least one catalyst effective in reducing the concentration of one or more gases in the exhaust gases, where at least one mat and at least one monolith are located within the frame element with at least one mat between the monolith and each adjacent wall, each blocking element is located across the inlet end or outlet end of the frame element and is connected to two opposite sides of the frame element.

In a second aspect, the present invention relates to a catalytic module comprising a plurality of frame elements in accordance with the first aspect of the present invention.

In another aspect, the present invention relates to an exhaust system comprising a frame member in accordance with a first aspect of the present invention.

In yet another aspect, the present invention relates to an exhaust system comprising a catalyst module in accordance with a second aspect of the present invention.

In another aspect, the present invention relates to a method for manufacturing a frame element in accordance with a first aspect of the present invention.

In another aspect, the present invention relates to a method for manufacturing a catalyst module in accordance with a second aspect of the present invention.

In yet another aspect, this invention relates to a method for treating exhaust gases, the method comprises passing exhaust gases through monoliths in a frame member in accordance with a first aspect of the invention, wherein the monoliths comprise one or more catalysts effective in reducing the concentration of one or more gases in exhaust gases.

In another aspect, this invention relates to a method for increasing the amount of catalyst in contact with exhaust gases, the method comprising passing exhaust gases through a catalytic module in accordance with a second aspect of the invention.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a 3D view of a catalytic module.

FIG. 2 is a diagram showing the arrangement of modules in a cross section of the outlet duct.

FIG. 3 is a diagram showing a top view of an arrangement of five groups of modules arranged one after another in the direction of gas flow inside the outlet duct.

FIG. 4 is a 3D view of a frame element.

FIG. 5 is a 3D view of a frame element with four monoliths in a frame element.

FIG. 6 is a view of a portion of a frame member shown from the inlet and / or outlet side, showing two portions, each with adjacent walls and cutouts on the inlet and / or outlet side.

FIG. 7 is an end view of a frame element with a locking element attached.

FIG. 8 is a side view of a frame element.

FIG. 9 is a cross-sectional view of a frame element with two monoliths in a cross-section of a frame element.

FIG. 10 is a cross-sectional view of a projection on a frame member.

FIG. 11 is a side view of a frame element containing four monoliths.

FIG. 12 is a side view of a frame member containing six monoliths.

FIG. 13 is a three-dimensional view of a frame element having a protruding portion on each side for connecting the frame element to other frame elements.

FIG. 14 is a view of two interconnected cutout blocking elements.

FIG. 15 is a 3D view of three frame elements with sides having a protruding portion for connecting the frame element to other frame elements, where the frame elements comprise monoliths.

DETAILED DESCRIPTION OF THIS INVENTION

As used in this description and in the appended claims, the singular is intended to include the plural, unless the context clearly indicates otherwise. Accordingly, for example, reference to "catalyst" includes a mixture of two or more catalysts, and the like.

The term "substantially all" means at least 90%, preferably at least 95%, preferably at least 97%.

The term "carrier" means an inert material on which the catalyst is supported.

The term "frame element" means a structure containing four walls, each wall containing a plurality of protrusions, where the four walls form a rectangular or square shape and define the interior space of the frame element in such a way that they contain a plurality of monoliths, each of which has at least one mat, covering part of each side of the monolith. The frame element may also comprise a blocking element on the inlet side of the cross section, which is used to protect the mat material from the direct kinetic energy of the direct flow and to act as a cross member for high mechanical stability. The frame element can be made of steel, where the steel is any of the various steel grades.

The term "blocking element" means a structure that supports a monolith in a frame element. The blocking element is usually made of the same material as the frame element, i.e. from any steel from various grades.

The term "cutout" means a portion or section of the frame member or blocking member that is not present and provides a reduction in the surface area of the frame member or blocking member with respect to the exhaust gas flow when the frame member or blocking member is installed in the exhaust stream. The cutout increases the number of cells in the monolith that are directly exposed to the flow of the exhaust gas. The term "directly exposed" means that the exhaust gases enter the cells in the monolith at the openings on the inlet side of the monolith.

“Mat” is to be understood as meaning a combination of mineral glass or metal fibers, for example in the form of a woven fabric, knitted fabric, irregular layer or the like. A mat can also refer to a fabric, fleece, or nonwoven fabric. The fibers used include a material that can withstand high temperatures and is corrosion resistant. They can include, in particular, an iron-based material to which alloying elements have been added, with at least one alloying element advantageously present, selected from nickel (8-11 wt.%) Or chromium (17-24 wt.%) ... One example of suitable fibers contains 70 wt% iron, 17 wt% chromium and 8 wt% nickel, although common impurities may of course also be present. The mat can be made by using fibers that are the same or different (for example, in terms of fiber length and fiber diameter). The fibers used may also contain mineral or glass based material. The mat can be in the form of a single piece, or it can be in the form of stripes, where the stripes cover the entire side or part of one or more sides of the monolith, or surround only part of the monolith.

The term "catalytic module" means a structure formed by a plurality of frame members or containing a plurality of frame members.

In a first aspect of the present invention, a frame member for supporting monoliths containing catalysts in the exhaust gas stream from combustion sources comprises two pairs of opposing walls, where the walls form a rectangular or square shape, an interior space defined by the walls, an inlet end, an outlet end, at least one blocking element, at least one mat, and at least one monolith comprising an inlet, an outlet, four sides, and at least one catalyst effective in reducing the concentration of one or more gases in the exhaust gas, where at least one mat and at least one monolith is located within the frame element with at least one mat between the monolith and each adjacent wall, each blocking element is located across the inlet end or the outlet end of the frame element and connected to two opposite sides of the frame element. The at least one wall, preferably each wall, can comprise a plurality of projections that extend into the interior of the frame element. The plurality of protrusions can be configured to contact the mat and support the mat on a monolith containing one or more catalysts when the monolith is positioned in the interior of the frame member.

FIG. 4 is a 3D view of a frame element. The frame element comprises four walls and for one or more, preferably all of the walls, may comprise a plurality of protrusions extending into the interior space defined by the four walls. The frame member can support a plurality of monoliths in the interior space defined by the four walls, as shown in FIG. 5, 11 and 12. The frame element can support monoliths in various configurations such as 1 to 2, 1 to 3, 3 to 3, etc. The length (depth) of the frame element is based on the length of the monoliths and the number of monoliths that can be placed in series in the frame element.

When two or more monoliths are in the interior space of the frame element, and at least two monoliths are located adjacent to each other, at least one mat can be positioned between the monoliths that are adjacent to one another. Preferably, at least a portion of one or more mats are located: (a) between each side of the monolith and an adjacent monolith; and (b) between each monolith and an adjacent wall of the frame element.

The frame element can be formed by joining four walls to one another to form a rectangular or square shape having an interior space. Preferably, the frame element can be formed by joining two parts, each of which contains two walls, together. FIG. 6 shows a view from the inlet end or the outlet end of two parts (A and B), each of which contains two walls formed by bending a single part. The walls are not shown because they are elongated in the figure and are hidden by the inlet and / or outlet portions of the frame element that are curved towards the inside of the frame element. The portions of the frame element at the entrance and exit of the frame element preferably comprise one or more cutouts that can increase the area of exposure of the monoliths located within the frame element. The cutouts of the frame member on the inlet and outlet side can reduce the number of cells in the monolith that are not exposed to the direct flow of the exhaust gas. Preferably less than 10%, more preferably less than 8%, even more preferably less than 7%, even more preferably less than 6%, most preferably less than 5% of the catalyst cells are not directly exposed to the exhaust gas stream.

Reducing the number of cells in the monolith that are not directly exposed to the gas stream can result in lower back pressure, increased exposure of the exhaust gases to catalysts, and higher conversion of compounds in the exhaust gases to other more desirable compounds.

The portions containing the wall can be joined together, preferably by welding.

FIG. 7 shows an upstream or downstream end view of a frame element with two attached locking elements. Monoliths with their side wall at least partially covered with mats are placed inside the walls of the frame element. Each blocking element can be connected to each of the four sides by welding. The blocking elements shown in FIG. 7, do not have cutouts. Preferably, the blocking elements will comprise one or more cutouts.

FIG. 8 is a side view of a frame element where the wall of the frame element has a length that is about the same as the length of the monolith. The width of the frame wall depends on whether there is a single monolith, or more monoliths, preferably two or three, adjacent to one another opposite the wall. When only a single monolith is placed against the wall, the width of the wall is approximately equivalent to the size of the monolith opposite the wall plus the thickness of the two mats. When multiple monoliths are positioned against a wall, the width of the wall is roughly equivalent to the sum of the dimensions of the monoliths along the wall plus the number of monoliths times the thickness of the two mats. Depending on how the walls are connected, it may be necessary to make adjustments for the wall thickness and manufacturing tolerance of the monoliths.

FIG. 9 is a cross-sectional view of a frame element showing the channels through the monoliths and projections in the walls of the frame element. In this drawing, two monoliths are positioned side by side with their flow channels having the same flow direction. The section in the drawing designated "Z" is shown enlarged in FIG. 10 to show details of the projections.

Two or more monoliths may be positioned in series within the frame element as shown in FIG. 11 and 12. The frame member may comprise a plurality of monoliths, where two or more monoliths are positioned such that the outlet of the first monolith is adjacent to the inlet of the second monolith and the exhaust gas flow passes through at least two monoliths in series. When three or more monoliths are used, the exhaust gases exiting the second monolith may enter the third monolith. In these configurations, one or more monoliths may be located downstream of the one or more monoliths in the direction of flow of exhaust gases through the monoliths in the frame member.

The frame element may contain a plurality of monoliths, where two or more monoliths are positioned such that the outlet of one monolith is adjacent to the inlet of another monolith, and the monoliths contain catalysts having the same functionality. The term "having the same functionality" means that catalysts adjacent to one another perform the same type of chemical reactions, such as selective catalytic reduction (SCR), ammonia oxidation, hydrocarbon oxidation, NO _x occlusion, oxygen occlusion, etc.

The frame element may contain a plurality of monoliths, where two of two or more monoliths are positioned such that the outlet of one monolith is adjacent to the inlet of another monolith, and the monoliths contain catalysts having different functionality. The term "having different functionality" means that catalysts located adjacent to one another perform different types of chemical reactions. Numerous configurations are possible. For example, a monolith containing catalysts for selective catalytic reduction (SCR) can be followed by a monolith containing catalysts for the oxidation of ammonia. A monolith containing catalysts for the oxidation of hydrocarbons may be followed by a monolith containing catalysts for selective catalytic reduction (SCR). A monolith containing a catalyst providing NO _x occlusion may be followed by a monolith containing catalysts for selective catalytic reduction (SCR). Other possible combinations of catalysts are known to those skilled in the art.

At least one wall of the frame element may comprise an elongated section, this elongated section containing a plurality of holes, where the holes are configured to allow the fastening element to pass through an opening to connect the frame element to another frame element.

The at least two walls of the frame element may comprise an elongated section containing a plurality of holes, where the holes are configured to allow the fastening element to pass through an opening to connect the frame element to another frame element.

Each of the four sides of the frame element may comprise an elongated section containing a plurality of holes, where the holes are configured to allow the fastening element to pass through the hole to connect the frame element to another frame element.

The elongated sections can be present on the inlet side, the outlet side, or both the inlet and outlet sides of the frame member. FIG. 13 shows a frame element where each of the sides (30) comprises an elongated section (34) containing a plurality of holes. Two types of holes, circular holes and slots, are shown in FIG. 13. Other shapes or combinations of shapes can be used.

Protrusions

One of the plurality of walls, preferably each wall, may comprise a plurality of protrusions extending into the interior space.

The number and size of the wall ridges can vary depending on several factors including, but not limited to, the physical properties of the mat, the size of the mat and the number of mats used per wall, and the wall size of the frame member. FIG. 7 shows a frame element with each wall having 25 projections in a 5 × 5 matrix.

The function of the protrusions is to support the mat between the wall and the monolith to prevent shear from breaking or damaging the monolith. When a single mat is used to cover all four sides of the monolith, fewer protrusions may be required than when two or more mats are used to cover each side of the monolith. If the mat is in the form of strips, where two or more strips are applied on the side of the monolith, more protrusions may be required than when a single mat is used to cover all four sides of the monolith. FIG. 9 is a cross-sectional view of a projection on a frame member, where the projection has a height (h) and a base width (w). The greater the height of the lip in relation to the base area of the lip, the more likely it is that the lip can compromise the integrity of the mat during normal use due to vibration. However, a protrusion that is low in height relative to the base area of the protrusion may be less likely to compromise the integrity of the mat during normal use, and a relatively large base helps to improve contact with a larger surface area of the mat. The height of the projection may be about 1 mm and the projection may be about 6 mm wide. Depending on the properties of the mat, the wall thickness of the frame element and the material, projections with different heights and widths can be used, such as, for example, 2 mm x 10 mm or 1 mm x 10 mm. The mat can be divided into large strips having a width of about the same as the thickness of the monolith. The mat can then be wrapped around the monolith and then the mat-covered monolith can be positioned in the frame element. The mat can also be present as two or more strips, where the total width of the strips is less than or equal to the thickness of the monolith. When two strips are used, and the total width of the strips is less than the thickness of the monolith, it is preferable that the strips are located off-center. The frame member is compressed and then the sides are welded together and the blocking member is welded to the four walls of the frame member at the inlet end and outlet end.

The frame element in accordance with this invention has improved open front surfaces for the application of the exhaust gas catalyst, while providing improved mechanical stability with respect to shock and vibration.

Monolith

The term "monolith", also known as a "honeycomb" type catalyst, means a carrier having a plurality of thin, parallel gas flow channels extending from the inlet to the outlet surface of the monolith such that the channels are open for fluid flow. The monolith can have a rectangular, preferably square, cross-section and a surface for flowing in. The surface of the monoliths can be of any size, preferably between 10 cm and 30 cm, inclusive. The length of the monolith in the direction of flow is usually in the range from 15 cm to 150 cm, although other lengths can be applied. The width of the frame element in the direction of flow of the exhaust gases is approximately equal to the length of the monolith.

The monolith has an inlet, an outlet, four sides, and multiple flow channels (or "cells"). Monoliths can contain up to about 700 or more channels per square inch of cross section, although much less can be used. For example, for stationary applications, the carrier typically can have from about 9 to 600, more typically from about 35 to 300, cells per square inch ("cells / square inch"). The channels, which are substantially straight paths from their fluid inlet to their fluid outlet, are defined by walls that are coated with one or more catalysts effective for treating exhaust gases as a "porous oxide coating" so that the gases flowing through the channels are in contact with the catalytic material.

One of ordinary skill in the art is familiar with the use and selection of one or more catalysts to reduce emissions of nitrogen oxides, carbon monoxide, hydrocarbons, ammonia and other pollutants to form nitrogen, water and carbon dioxide, which are relatively harmless compounds. The monolith may contain one or more catalysts of a selective catalytic reduction (SCR) catalyst, an ammonia oxidation catalyst, a hydrocarbon oxidation catalyst, a NO _x occlusion catalyst, an oxygen occlusion catalyst, etc. The monolith can be a filter such as a ceramic filter. Other types of catalyst may be present. The flow channels in a monolithic base are thin-walled channels that can have any suitable cross-sectional shape such as trapezoidal, rectangular, square, triangular, sinusoidal, hexagonal, oval, circular, etc. This invention is not limited to a particular type, material or geometry of the substrate. The monolith is usually an extruded material, preferably a ceramic base.

Ceramic substrates can be made from any suitable refractory material such as cordierite, cordierite-α-alumina, α-alumina, silicon carbide, silicon nitride, zirconia, mullite, spodumene, alumina-silica-magnesium oxide, zirconium silicate, sillimanite, magnesium silicates, zircon, petalite, aluminosilicates and mixtures thereof. The ceramic base can have catalytic activity by itself. In some cases, additional catalytic material is not placed on ceramic substrates that have catalytic activity.

Mats

One or more mats can form a seal that restricts the movement of exhaust gases around the monolith. The mats can prevent direct physical contact between the monolith and the frame element and provide damping against shock and vibration applied to the frame element by external forces. Mats that can be used in this invention are known in the art.

A single mat can cover essentially all four sides of the monolith. At least most of each of the four sides of the monolith may be matted. A single mat can cover essentially all four sides of the monolith. One or more parts of the mat may surround all or nearly all of the monolith. The mat may be in the form of stripes, and the stripes may only surround part of the monolith.

At least most of the area of at least one side of the monolith may be covered with one or more mats.

At least most of the area of each of the at least two sides of the monolith may be covered with one or more mats.

At least most of the area of each of the four sides of the monolith may be covered with one or more mats.

The thickness of the mat can be selected such that the mat fills the gap between the monolith and the frame element and provides cushioning that allows the monolith to resist surface pressure of at least about 100, preferably about 150, more preferably about 200 N / mm ² surface pressure when the frame element is compressed during assembly.

The thickness of one or more mats that are used with the monolith can be determined based on the size of the monolith with which the mat is in contact. Monoliths are commercially available in various sizes, with manufacturing tolerances for each monolith size varying from manufacturer. A monolith with a cross-section of 150 × 150 mm can have a manufacturing tolerance of ± 3 mm. By providing mats of different thicknesses, for a monolith having an actual cross section of 149 x 149 mm, a mat that is thicker than that used for a monolith having a cross section of 153 x 153 mm can be used. The mat used for a monolith having an actual cross section of 153 x 153 mm may be thinner than a mat used for a monolith having an actual cross section of 150 x 150 mm.

When the monolith has a nominal width N and an actual width A, the thickness of the mat used with a monolith having an actual width A equal to the nominal width N is B, and the desired thickness of the mat used with a monolith having an actual width C is:

a) B + (A-C) when C <A;

b) B when C = A; and

c) B - (C-A) when C> A,

where the actual thickness of the mat used with the monolith having the actual width C is the closest thickness of a commercially available material mat of width B.

Two mats can be used to achieve the desired thickness.

Blocking element

The frame element comprises one or more blocking elements, where each blocking element extends along the inlet end and / or the outlet end of the frame element and is connected to opposite walls of the frame element. The blocking elements support the monoliths within the frame element and prevent the opposing walls of the frame element from moving. FIG. 5 and 13 show each frame element containing four monoliths in a 2 by 2 configuration with two blocking elements, where each blocking element is located over the sides of two adjacent monoliths and the gap between the monoliths. In the case of a frame member with 1 to 3 monoliths, each of the inlet side and the outlet side may contain two blocking members, with each blocking member being positioned over a gap between two adjacent monoliths.

The blocking elements preferably comprise one or more cutouts. The notch provides an increase in the number of sections in the monolith that are directly exposed to the exhaust stream when the catalytic module is exposed to exhaust gases from the exhaust source. When the blocking element does not contain cutouts, more sections in the monoliths are covered with the blocking element, and this reduces the number of sections that come into direct contact with the exhaust gases. The width of the cutout of the blocking element is such that the gap between the monoliths is covered. When determining the cutout width, the manufacturing tolerance of the monolith widths must be taken into account. The blocking elements located on the frame element at the inlet and outlet (inlet and outlet side) may contain cutouts such that preferably less than 10%, more preferably less than 8%, even more preferably less than 7%, even more preferably less than 6%, most preferably less than 5% of the catalyst sections are not directly affected by the exhaust gas stream. This results in lower back pressure and higher utilization of the catalyst monoliths and therefore higher conversions.

When at least one of (a) the walls of the frame member on the inlet side and the outlet side of the frame member (as shown in FIGS. 6, 7 and 13) and (b) the blocking member (as shown in FIGS. 13 and 14), contains a notch, the conversion value of at least one of NH ₃ , NO _x , hydrocarbons and carbon monoxide is greater than that of the comparative frame member having no notches.

FIG. 7 shows an upstream or downstream end view of a frame element with two attached locking elements. Monoliths with their side wall at least partially covered with mats are placed inside the walls of the frame element. Each blocking element can be connected to opposite walls by welding. The blocking element is preferably welded to the frame element under prestressing that minimizes or prevents swelling of the frame element. Swelling of the frame member can lead to lower surface pressures and thus a higher risk of displacement of monoliths under the influence of intermittent mechanical stresses such as shock and vibration under typical operating conditions of the exhaust system.

Catalytic module

In another aspect of the present invention, the catalytic module may comprise a frame element in accordance with the first aspect of the present invention.

The catalytic modules of the present invention can belong to one of two groups: having a peripheral frame and without a peripheral frame.

Peripheral frame catalyst modules are known in the art, as shown, for example, in FIG. 1. Catalyst modules with a peripheral frame may have two sides 10, an upper part 11, a lower part 12 and a number of spaces 15 defined by horizontal baffles 13 and vertical baffles 14. A frame element in accordance with the first aspect of the present invention, comprising a plurality of monoliths containing one or more catalysts may be inserted into each of the spaces 15. Preferably, the frame members comprise one or more blocking members as described above.

A catalytic module without a peripheral frame can be formed by combining a plurality of frame members with one another by positioning the frame members adjacent to one another and positioning the frame members on top of other frame members and connecting the frame members to the adjacent frame members (see FIG. 15). A catalytic module without a peripheral frame is particularly useful when only a small number of monoliths are required and it is possible to avoid the excessive weight and complexity of the catalytic module with a peripheral frame.

Preferably, the frame members are connected to adjacent frame members. Adjacent frame members may have a sealing member, such as a mat, between them. The frame element can be connected to adjacent frame elements by means of welding, adhesives that can withstand the temperatures, vibrations and impacts that the catalytic modules are subjected to when positioned in the exhaust stream, or mechanical means such as bolts, nuts, anchors, etc. .d. Preferably, one or more sides of the frame elements comprise a projecting portion.

The frame members in the catalytic module can be positioned to minimize the flow of exhaust gases in a circumferential manner around the frame members when the catalytic module is installed in the exhaust system.

The catalytic module may comprise a plurality of frame elements, where at least one wall of the frame element comprises an elongated section containing a plurality of holes, where the holes are configured to allow the fastener to pass through an opening to connect the frame element to another frame element, and each frame element is connected with one or more frame members along an extended section of frame members.

The catalytic module contains a plurality of frame elements, where at least one wall of the frame element comprises an elongated section containing a plurality of holes, where the holes are configured to allow the fastening element to pass through an opening to connect the frame element to another frame element, and the frame elements are thus arranged that there is a minimal passage of exhaust gases in a roundabout manner around the frame elements.

The catalytic module may comprise a plurality of frame elements, where at least two walls of the frame element comprise an elongated section containing a plurality of holes, where the holes are configured to allow the fastening element to pass through an opening to connect the frame element to another frame element, and the frame elements are positioned as such in such a way that there is a minimum passage of exhaust gases in a roundabout manner around the frame elements.

The catalytic module may comprise a plurality of frame elements, where at least each of the four sides of the frame element comprises an elongated section containing a plurality of holes, where the holes are configured to allow the fastener to pass through an opening for connecting the frame element to another frame element, and the frame elements arranged in such a way that there is a minimum passage of exhaust gases in a roundabout manner around the frame elements.

Each of the frame members in the catalyst module may be coupled to an adjacent frame member when the frame members comprise an elongated section containing a plurality of holes, where the holes are configured to allow the fastener to pass through an opening to connect the frame member to another frame member.

Each of the frame members in the catalytic module can be connected to all adjacent frame members when the frame members comprise an elongated section containing a plurality of holes, where the holes are configured to allow the fastener to pass through the hole to connect the frame member to another frame member.

The catalytic module may further comprise a plurality of spaces defined by horizontal baffles and vertical baffles, where a frame element containing a monolith and one or more mats located between each side of each monolith is present within the space.

The catalytic modules can be fixed directly in the outlet or in a larger reaction space, called a reactor, in the exhaust gas stream.

The exhaust system may include a frame member in accordance with the first aspect of the present invention.

The exhaust system may comprise a catalytic module comprising a frame member in accordance with the first aspect of the present invention.

When the monolith in the frame member, alone or in the catalytic module, contains a selective catalytic reduction (SCR) catalyst, the exhaust system may further comprise means for injecting a reducing fluid, such as a hydrocarbon or nitrogen-containing reductant, or a precursor thereof, into the exhaust gases above downstream of the frame element. Preferably, this tool contains an injector. One of ordinary skill in the art will understand that ammonia or some other type of reducing agent is required when a selective catalytic reduction (SCR) catalyst is used to convert nitrogen oxides to nitrogen. Such a person skilled in the art will understand how to add the reactant to the exhaust gases and apply a selective catalytic reduction (SCR) catalyst in this system. Such a person skilled in the art will also appreciate that means for injecting a reducing fluid into the upstream exhaust gases are well known in the art.

In another aspect, the present invention relates to a method for manufacturing a frame element in accordance with a first aspect of the present invention. A method for producing a frame element in accordance with a first aspect of the present invention includes wrapping each monolith with a mat, placing the wrapped monolith within the interior of the frame element before the blocking element is connected to the frame element, and connecting the blocking elements to the frame element while the frame element is the element containing the mat-wrapped monolith is subjected to a compressive force. Preferably, the frame element is compressed at a pressure of at least about 100 N / mm ² , preferably at least about 150 N / mm ² , more preferably at least about 200 N / mm ² , depending on the nature of the mat.

In another aspect, this invention relates to a method for manufacturing a catalyst module comprising a plurality of frame members in accordance with a first aspect of the present invention. This method includes forming a frame element containing one or more monoliths, one or more mats and one or more blocking elements by wrapping each monolith with a mat, placing the wrapped monolith inside the frame element, connecting one or more blocking elements to the frame element, while that a frame element containing a mat-wrapped monolith is subjected to a compressive force, and (a) joining one or more frame elements to one another to form a catalytic module, or (b) introducing a frame element containing one or more blocking elements into a partition in the frame in the catalytic module. Preferably, the frame element is compressed at a pressure of at least about 100 N / mm ² , preferably at least about 150 N / mm ² , more preferably at least about 200 N / mm ² , depending on the nature of the mat. One of ordinary skill in the art will understand the techniques and procedures used to manufacture a catalyst module having a peripheral frame, where the frame members described above may be located within the baffles in the frame member. Those skilled in the art will also understand the techniques and procedures used to connect frame members comprising a projecting portion as described above to one another using mechanical fasteners.

A method for treating exhaust gases includes passing exhaust gases through a monolith within a frame member in accordance with a first aspect of the present invention, wherein the monolith comprises one or more catalysts effective in reducing the concentration of one or more gases in the exhaust gas.

A method for increasing the amount of catalyst in contact with exhaust gases includes passing exhaust gases through a frame member in accordance with a first aspect of the present invention, wherein the frame member comprises a recess.

This invention may also be defined in accordance with one or more of the following definitions:

1) A frame element for supporting monoliths containing catalysts in the flow of exhaust gases from combustion sources, this frame element contains two pairs of opposite walls, where the walls form a rectangular or square shape, the inner space formed by the walls, an inlet end, an outlet end at least at least one blocking element, at least one mat, and at least one monolith comprising an inlet, an outlet, four sides and at least one catalyst effective in reducing the concentration of one or more gases in the exhaust gas, where at least one the mat and at least one monolith are located within the frame element with at least one mat between the monolith and each adjacent wall, each blocking element is located across the inlet end or the outlet end of the frame element and connected to two opposite sides of the frame element.

2) Frame element according to item 1), where two or more monoliths are located in the inner space of the frame element, at least two monoliths are located adjacent to each other, and at least one mat is located between the monoliths, which are located adjacently one next to others.

3) The frame element according to 1) or 2), where at least two locking elements are located at the inlet end of the frame element and at least two locking elements are located at the outlet end of the frame element.

4) A frame element according to any one of items 1) to 3), where, when the frame element contains at least two monoliths, a space is formed between adjacent monoliths, and at least one of the blocking elements is located over, and preferably in the center, the space between two monoliths.

5) A frame element according to any one of items 1) to 4), where each blocking element is connected to opposite walls by means of welding.

6) The frame element according to any one of items 1) to 5), wherein the blocking element comprises a cutout, where the cutout provides an increase in the number of sections in the monolith that are directly exposed to the exhaust gas stream when the catalytic module is exposed to exhaust gases from the exhaust gas source.

7) A frame element according to any one of paragraphs 1) to 6), where at least one element of (a) the walls of the frame element at the inlet and outlet of the frame element and (b) the blocking element contains a cutout, and the conversion value of at least one from a compound of NH ₃ , NO _x , hydrocarbons and carbon monoxide is greater than the value for the comparative frame element without cutouts.

8) A frame element according to any one of items 1) to 7), where each wall contains a plurality of protrusions extended into the interior space.

9) The frame element of claim 8), wherein the plurality of projections are configured to contact the fibrous mat and support the fibrous mat on a monolith containing one or more catalysts when the monolith is positioned in the interior of the frame member.

10) A frame element according to any one of items 1) to 9), where at least one wall of the frame element comprises an elongated section containing a plurality of holes, where the holes are configured to allow the fastening element to pass through an opening to connect the frame element to another frame element ...

11) A frame element according to any one of items 1) to 10), wherein at least two walls of the frame element comprise an elongated section containing a plurality of holes, where the holes are configured to allow the fastening element to pass through an opening to connect the frame element to another frame element ...

12) The frame element according to 1) to 11), where each of the four sides of the frame element comprises an elongated section containing a plurality of holes, where the holes are configured to allow the fastener to pass through the hole to connect the frame element to another frame element.

13) A frame element according to any one of items 1) to 12), wherein at least a large part of the area of at least one side of the monolith is covered with one or more mats.

14) A frame element according to any one of items 1) to 13), wherein at least most of the area of each of the at least two sides of the monolith is covered with one or more mats.

15) A frame element according to any one of items 1) to 14), wherein at least most of the area of each of the four sides of the monolith is covered with one or more mats.

16) The frame element according to any of paragraphs 1) - 15), where the mat is in the form of stripes, and the stripes surround only part of the monolith.

17) A frame element according to any one of items 1) to 16), wherein the thickness of the mat is chosen such that the mat fills the gap between the monolith and the frame element and provides cushioning, which makes it possible for the monolith to resist surface pressure of at least about 100, preferably at least at least about 150, more preferably at least about 200 N / mm ² surface pressure when the frame member is compressed during assembly.

18) A frame element according to any one of items 1) to 17), where the monolith has a nominal width N and an actual width A, the thickness of the mat used with a monolith having an actual width A equal to the nominal width N is B, and the desired thickness of the mat, used with a monolith having an actual width C is:

a) B + (A-C) when C <A;

b) B when C = A; and

c) B - (C-A) when C> A,

where the actual thickness of the mat used with the monolith having the actual width C is the closest thickness of a commercially available material mat of width B.

19) A frame element according to any one of items 1) to 18), wherein one or more mats form a seal restricting the movement of exhaust gases around the monolith.

20) A frame element according to any one of items 1) to 19), wherein the monolith comprises a selective catalytic reduction (SCR) catalyst.

21) The frame element according to any one of paragraphs 1) to 20), where the monolith contains an oxidation catalyst.

22) A frame element according to any one of paragraphs 1) - 21), where the monolith is a filter.

23) The frame element according to any one of paragraphs 1) - 22), where the frame element contains a plurality of monoliths, and two or more monoliths are arranged so that the outlet of one monolith is adjacent to the inlet of another monolith, and the exhaust gas flow passes sequentially through at least at least two monoliths.

24) The frame element of item 23), wherein two or more monoliths are positioned such that the outlet of one monolith is adjacent to the inlet of another monolith, and the monoliths contain catalysts having the same functionality.

25) A frame element according to item 23), where two of two or more monoliths are positioned such that the outlet of one monolith is adjacent to the inlet of another monolith, and the monoliths contain catalysts having different functionalities.

26) A catalytic module containing a plurality of frame elements according to any one of paragraphs 1) - 25).

27) Catalyst module according to item 26), where the frame members are located to minimize the passage of exhaust gases around the frame members when the catalytic module is installed in the exhaust system.

28) A catalytic module comprising a plurality of frame members according to one or more of 10), 11) and 12), where each frame member is connected to one or more frame members along an elongated section of the frame members.

29) A catalytic module containing a plurality of frame members according to one or more of items 10), 11) and 12), where the frame members are arranged in such a way that there is a minimum passage of exhaust gases in a roundabout manner around the frame members.

30) The catalytic module according to any one of items 26) to 29), where each of the frame elements is connected to an adjacent frame element.

31) The catalytic module according to any one of items 26) to 29), where each of the frame members is connected to all adjacent frame members.

32) The catalytic module according to any one of paragraphs 26) - 31), where the catalytic module further comprises a plurality of spaces formed by horizontal partitions and vertical partitions, where a frame element containing a monolith and one or more mats located between each side of each monolith is present inside the space.

33) An exhaust system containing a frame element according to any one of paragraphs 1) - 25).

34) An exhaust system containing a catalytic module according to any one of paragraphs 26) - 32).

35) An exhaust system according to 33) or 34), further comprising means for generating NH ₃ in the exhaust gases, where the means for generating NH ₃ is located in front of the frame element or catalytic module.

36) A method for producing a frame element according to any one of items 1) -25), this method includes wrapping each monolith with a mat, placing the wrapped monolith inside the inner space of the frame element before the blocking element is connected to the frame element, and connecting the blocking elements to the frame element, while the frame element containing the monolith, wrapped with a mat, is subjected to a compressive force.

37) The method of claim 36), wherein the frame member is compressed at a pressure of at least about 100 N / mm ² , preferably at least about 150 N / mm ² , more preferably at least about 200 N / mm ² .

38) A method of obtaining a catalytic module according to any one of paragraphs 26) to 32), this method includes forming a frame element containing one or more monoliths, one or more mats and one or more blocking elements by wrapping each monolith with a mat, placing the wrapped monolith inside of the frame element, connecting one or more blocking elements to the frame element while subjecting the frame element containing the mat-wrapped monolith to a compressive force, and (a) connecting one or more of the frame elements to one another to form a catalytic module, or (b) introducing a frame member containing one or more blocking members into a baffle in the frame in the catalytic module.

39) The method of claim 38), wherein the compressive force is at least about 100 N / mm ² , preferably at least about 150 N / mm ² , more preferably at least about 200 N / mm ² .

40) A method for treating exhaust gases, the method comprises passing exhaust gases through a monolith within a frame element according to any one of 1) to 25), wherein the monolith comprises one or more catalysts effective in reducing the concentration of one or more gases in the exhaust gases.

41) A method of increasing the amount of catalyst in contact with the exhaust gases, the method comprises passing the exhaust gases through the frame member according to item 6) or 7).

Claims (19)

1. A frame element for supporting monoliths containing catalysts in the flow of exhaust gases from combustion sources, the frame element contains two pairs of opposite walls, where the walls are made with the possibility of forming a rectangular or square shape, the inner space formed by the walls, the inlet end, the outlet end, at least one blocking element, at least one mat, and at least one monolith comprising an inlet, an outlet, four sides and at least one catalyst effective in reducing the concentration of one or more gases in the exhaust gas, where at least one mat and at least one monolith are located in the inner space of the frame element so that at least one mat is located between the monolith and each adjacent wall, each blocking element extends across the inlet end or outlet end of the frame element and is connected to two opposite sides of the frame element , with one or more walls contains many protrusions that extend into the interior space. 2. An element according to claim 1, wherein each wall comprises a plurality of projections extending into the interior space. 3. The element according to claim. 1 or 2, in which two or more monoliths are located in the inner space of the frame element, at least two monoliths are located adjacent to each other and at least one mat is located between the monoliths, which are located adjacent to each other friend. 4. An element according to any one of the preceding claims, in which at least two locking elements are located at the inlet end of the frame element and at least two locking elements are located at the outlet end of the frame element. 5. An element according to any one of the preceding claims, wherein when the element comprises at least two monoliths, a space is formed between adjacent monoliths and at least one of the blocking elements is located over and preferably in the center of the space between two monoliths. 6. An element according to any one of the preceding claims, in which the thickness of the mat is chosen so that the mat is configured to fill the gap between the monolith and the frame element and provide cushioning, which makes it possible for the monolith to resist surface pressure of at least 100 N / mm ² surface pressure, when the frame element is compressed during assembly. 7. A member according to any of the preceding claims, wherein the monolith has a nominal width N and an actual width A, the thickness of the mat used with the monolith having an actual width A equal to the nominal width N is B, and the desired thickness of the mat used with the monolith, having the actual width C is: a) B + (A-C) when C <A; b) B when C = A; and c) B - (C-A) when C> A, in which the actual thickness of the mat used with the monolith having the actual width C is the closest to the thickness of a commercially available material mat of width B. 8. An element according to any one of the preceding claims, in which the monolith contains a selective catalytic reduction (SCR) catalyst; oxidation catalyst or filter. 9. An element according to any one of the preceding claims, comprising a plurality of monoliths, wherein two or more monoliths are positioned such that the outlet of one monolith is adjacent to the inlet of the other monolith and the exhaust gas flow passes through at least two monoliths in series. 10. An element according to claim 9, wherein two or more monoliths are positioned such that the outlet of one monolith is adjacent to the inlet of another monolith, and the monoliths comprise catalysts having the same or different functionality. 11. A catalytic module comprising a plurality of frame members according to any one of the preceding claims. 12. An exhaust system containing a frame element according to any one of paragraphs. 1-10 or the catalytic module of claim 11. 13. A method of obtaining a frame element according to any one of paragraphs. 1-10, the method includes wrapping each monolith with a mat, placing the wrapped monolith within the interior of the frame element prior to joining the locking element to the frame element, and connecting the locking elements to the frame element when subjecting the element containing the mat-wrapped monolith to a compressive force. 14. The method of obtaining a catalytic module according to claim 11, the method includes forming a frame element according to the method according to claim 13 and either: (a) connecting one or more frame elements to one another to form a catalytic module; or (b) introducing a frame member containing one or more blocking members into a baffle in a frame in the catalytic module. 15. A method for treating exhaust gases, the method includes passing the exhaust gases through a catalyzed monolith inside the frame element according to any one of claims. 1-10.

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